The Intercalary Fragment in Posterior Malleolus Fractures: Characterization and Significance

Methods of fixation in ankle fractures involving the posterior malleolus have become increasingly scrutinized. With the increase in computed tomography (CT), an intercalary fracture fragment (ICF) adjacent to the posterior malleolus has been oft described. Treatment of the ICF remains controversial and the purpose of this study was to evaluate radiographic and clinical outcomes in patients who had direct reduction and fixation of this fragment compared to those where the ICF was not fixed. This retrospective study included 249 trimalleolar and posterior pilon ankle fractures grouped into those who had the ICF reduced and fixed (n = 74) and those where the ICF was not directly addressed (n = 175). CT scans were evaluated for size and location of the ICF. Demographic, radiographic and intraoperative variables were collected and analyzed. The group which had the ICF reduced and fixed had decreased Kellgren-Lawrence scores (p = .001). There was also a higher rate of repeat surgery in the group who had the ICF fixed, although not meeting statistical significance. There were no differences in size or location of the ICF fragment between groups. We did identify similarities with other studies in regard to size and posterolateral location of the ICF between groups. However, based on worsening radiographic outcomes of the group where the ICF was reduced and fixed, we do not necessarily recommend universal treatment of this fragment. The surgeon's goal should always be a concentric articular reduction and treatment of the ICF should be considered on a case-by-case basis.